The present invention relates to surgical devices and more particularly to endoscopic retrieval devices constructed for retrieving relatively small pieces of sample tissue or foreign bodies from a human subject through orifices or small incisions.
Snares, baskets, and graspers are in widespread use for severing capturing and retrieving tissue specimens and foreign bodies from within subjects. The devices are used in human and animal subjects, in laparoscopic surgeries and other procedures where access within a subject is only possible via a small opening. One exemplary use is for cutting off and retrieving intestinal polyps where a wire snare, passed through an colonoscope instrument channel, encircles and is tightened about an intestinal polyp to sever the polyp. The severed polyp is retrieved in a net inserted through the instrument channel. The net is manipulated to enclose the polyp and then withdrawn with the instrument so that the tissue architecture remains undisturbed.
In this procedure, as well as others, the net and snare must be quite compact in order to pass into the subject through the instrument channel, or other passage. Prior art proposals have employed snares supported within plastic tubes that were snaked into the subject to locate the snare where desired. The snare was then deployed from its tube, manipulated to cut off the polyp and retrieved into the tube for removal from the subject.
A net, collapsed within another tube, was introduced through the instrument channel, etc., for removing the polyp. When near a target polyp, the net was deployed, like the snare, and manipulated to net the polyp. The net was then closed sufficiently to secure the polyp and withdrawn from the subject.
U.S. Pat. No. 5,643,283 to Younker, which is incorporated herein by reference in its entirety, discloses a device for retrieving an object from within a subject. The device comprises a shaft and a compressible pouch for receiving the object positioned adjacent a distal end of the shaft. The pouch includes a mouth which can be opened and closed. The pouch is retained, in proximity to the distal end of the shaft, on a cable loop by a slidable tether. The net is free to slide on the cable loop to form a pouch at the distal end of the shaft. The tether is fixed at a second location near the proximal end of the shaft, and in one embodiment, is tied off to a ring and secured with heat shrink tubing. When the targeted foreign object is within the pouch, a clinician disengages the ring portion of the handle to close the net around the object. The clinician then removes the device from the patient and unloads the object from the net. The clinician then places the ring on a post, in order to pack the pouch into the distal end of the shaft.
In operation of a commercial embodiment of U.S. Pat. No. 5,643,283, several problematic issues have surfaced. Clinicians have experienced difficulty in understanding the operation of the tether, in particular, the interaction of the ring and post. The ring is to be used to pull the net inside the shaft only when an object is not within the net. In preparation to capture an object, the ring should be disengaged to release the net. The net is then slid over the targeted object and the net is closed. At this point, proper operation would involve merely removing the device from the patient. However, some clinicians when operating the device try to further pull the net inside the shaft when the net is bundled up at distal end of cable loop. This will cause the net to jam, or in some cases, damages the tubing. The occasional improper operation of the device sometimes causes permanent malfunction.
The commercial embodiment discussed above also adds undesirable expense to the product. Specifically, the full length tether and heat shrink operation add material cost and labor assembly cost to the device.
The present invention provides a new and improved retrieval device that is so constructed and arranged that net movement during deployment and retrieval is not prohibitively restricted. Secure net attachment is assured and that provides for convenient net packing in the introducer passage. The device provides a convenient and economical method of sample retrieval during endoscopic procedures. The new retrieval device is easy assemble, manufactured at a reduced cost, and easier to use by the end consumer.
In one illustrated embodiment of the present invention an endoscopic surgical device for retrieving severed tissue from within a human subject is provided. The device includes a support unit and a tissue retrieving net system.
The support unit includes a body and an elongated introducer member. The body defines a first passage therethrough. The introducer has a first end section proximal and fixed with respect to the body and a second end section remote from the body. The introducer member further defines a second passage aligned with the first passage and opening at the second end section.
The tissue retrieving net system includes a net, a net deployment and retrieval assembly and a net actuator system.
The net includes a wire-like resilient loop and a net element having a mouth section slidably disposed on the loop and a tissue receiving pouch section. The loop terminates with two relatively parallel loop cables. The net is disposed adjacent the second end for deployment and retraction through the second passage opening.
The net deployment and retrieval assembly extends substantially through the first and second passages and connects to the net. The assembly further includes a motion transmitting member extending in the second passage to the loop.
The net actuator unit includes a first handle fixed with respect to the body and a second handle fixed with respect to the motion transmitting member and movable relative to the first handle. The act of shifting the second handle relative to the first handle shifts the net into and out of the second passage opening.
The introducer member second passage has a diameter substantially smaller than the width of the loop as deployed. The member engages the loop at the second end section opening and resiliently collapses and elongates the loop as the net is retracted and moves into the introducer member passage. The loop resiliently returns to its uncollapsed configuration as it is deployed.
In one embodiment, the net system includes at least one connector adapted to fasten each loop cable. The ends of the net element are secured to the motion transmitting member on the proximal side of the at least one connector with respect to the support unit.
In a second embodiment, the net system further includes a first connector, a second net connector proximal to the second passage opening, and an intermediate portion defined by an axial space on the loop cables between the first connector and the second connector. The first connector and the second connector are adapted to fasten each loop cable. Ends of the net element are secured to the loop within the intermediate loop portion between the first connector and the second connector.
The deployment and retrieval assembly may include a thin, flexible wire-like motion transmitting member between the net actuator unit and the loop. The motion transmitting member extends within an introducer guide passage which closely surrounds the motion transmitting member and constrains the member for translational longitudinal motion within the passage.
The first connector may be disposed at least 6 inches from the second connector, such that only one connector is within an articulation zone during deployment of the net element.
The ends of the net element may be secured to the motion transmitting member adjacent a proximal shoulder of the connector with respect to the support unit.
The present invention offers advantages over devices available in the prior art. In a second embodiment, the net is fixed distally and proximally by the use of a first and second connector. The connectors are sufficiently spaced apart to provide secure net attachment without the use of additional tether mechanisms. The connectors are positioned such that only one may be within an articulation zone of the endoscope at a time, permitting ease of net deployment in a variety of geometric operating configurations.
In a first embodiment, only one connector is used to secure the proximal side of the net. This technique decreases the amount of cable loop length within the articulation zone. The reduction in cable loop length effectively reduces the amount of rigid material within the articulation zone of the endoscope at a time, further permitting ease of net deployment in a variety of geometric operating configurations.
The device is also easier to assemble and less expensive to manufacture than certain conventional designs.
Further features and advantages of the invention will become apparent from the following detailed description made with reference to the accompanying drawings.